Method of forming laminated sheet bodies



Nov. 30, 1943. F. M. wElR METHOD OF FORMING LAMINATED SHEET BODIES Filed Janl so, 1941 2 sheets-sheet 1 Pi G.3

f/'u /vc/s M WE/R INVENTOK BY QUA* www ATTORNEY Nov. 30, 1943. F. M. wElR METHOD oF FORMING LAMINATED SHEET4 BODIES 2 sheets-sneek 2 Filed Jan'. so, 1941 `Fi G.8

FRANC/s M WE/R INVENTOR. QL /f WW ATTORNEY ?atenteol Nov. 3ds, i943 Francis M. Weir, Brooklyn, N.-Y., assigner, by

direct and mesme assignments, to lVIarine-Air` Research ilorporation, Annapolis, Md.

appagante .ranuary 3o, 1941, serial No. 316,586

(ci. iti- 30er 2 Glaims.

My invention relates to methods and devices for forming laminated sheet bodies and has particular reference to the making of composite sheets and hollow objects by cementing together sheets of a fibrous material, such as wood veneer.

It has been found that veneer represents a very good material for forming'hollow bodies, such as pontoons, boats, airplane fuselages, etc.. by cementing together two or more layers of veneer. In forming curved bodies, especially having a double curvature, it was found necessary to apply heat and pressure to the veneer layers in special moulds by placing the moulds or dies with the veneer in autoclaves. This method is very expensive, however, and, besides, ithas a disadvantage in that it is diilicult to avoid overlapping of the veneer layers, the overlapped joints causing irregularities in the surface of the article and preventing proper adhesion at the sides of the overlapping joint.

I have found that better results can be btained by using a special device for successively heating and cementing different portions of the product. Veneer sheets are placed OT this D111'- pose on a mould and temporarily held in place, with a layer or coating of a thermoplastic material between the layers. Heat is then applied locally to one portion of the veneer until the thermoplastic vmaterial is softened, the softened portion being then compressed or rolled, being at the same time cooled for hardening the cement.

My invention is more fully described in the accompanying specication and drawings, in which:

Fig. 1 is an elevational view of my device in operation;

Fig. 2 is a top plan view of the same;

Fig. 3 is a sectional elevational view of a modied device;

Fig. 4 is a sectional view of another modification;

Fig. 5 is a diagrammatic view of rolls for making continuous sheets;

Fig. 6 is a side view of the rolls for making corrugated sheets;

Fig. 7 is a side View of the rolls for making angles and similar shapes;

Fig. 8 is a modied device employing an electric vibrator;

Figs. 9 and 10 are views of a ment.

My device for forming laminated bodies consists of a frame I having a handle 2 forits manual operation. A heating pad 3 is supported at modied arrange- II inside.

the end of the frame and consists of a hollow metal block having an electric heating element Leads from the heating element are connected to a receptacle 5 for a plug 6 with cords 1 extending to the outside through aY centrai hoiein the handle 2.

The middle portion of theframe I has bearings 8 at the ends for trunnions 9 of a hollow roll I0. The trunnions are also hollow and have openings II in communication with inner annular grooves `I2 in the bearings 8. The grooves are connected with pipes I3 and ldheld in the bearings, the pipes extending to the outside through the central hole in the handle 2. The pipe I3 is used for delivering cooling liquid into the roll l0, the pipe I4 exhausting the liquid, so that the latter may be made to circulate continuously through the roll for its cooling.

My device is preferably used for building up hollow structures from a thin wood veneer. Layers or sheets I5 and It of such veneer are placed over a mould orA frame il, the contacting surfaces of the veneer sheets being coated as by spraying with a layer I8 of a thermoplastic cementitious material having preferably its softening point well above ordinary temperatures, as, for instance, or 140 F. The veneer is placed on the mould and is temporarily held in place, as, for instance, by the operators left hand. The device is then placed on the veneer with the heating pad over a starting point. The heat melts or softens the .cementitious material I8, permitting the veneer to be cemented together by the application of pressure. This is accomplished by passing the roll I0 over the heated spot with the application of a suitable pressure until the veneer sheets are glued together, the cold roll I0 hardening the material i8.

The roll I0 may be replaced with a cooling box i9, Fig. 3, the box being hollow and provided with cooling fins 20. The latter may be further cooled by the draft from a fan 2l operated by a small electric motor 22.

In another modication shown in Fig. 4, the

hollow roll 23 is entirely enclosed and provided.

with a hole at the end closed with a screw plug 24. The roll can be filled with a cooling liquid such as brine, with ice or with frozen carbon dioxide ("dry ice).

The heating pad may be heated in any suitable manner and may be provided, fo; instance, with a' gas or kerosene burner.

My method can be also used for joining wood or other brous material with metal sheets or sheets made of a synthetic plastic material. Fig.

5 shows an application o! my( method to the manufacturing of continuous sheets. Rolls 23 are used for this purpose operated by a suitable source of power (not shown) for rollin! veneer sheets 28 and 2l. "'he sheets are heated before rolling between stationary heating blocks 28 and 29.

Corrugated rolls 30, Fig. 6, may be employed for making corrugated veneer or other laminated sheets. v

Built-up veneer angles and similar shapes can be manufactured by rolling thin strips between specially shaped rolls 3| and 32, Fig. '7.

A modiied device is shown in Fig. 8. having a cold pressure block 33 with an electric motor 34 operating a vibrator 35. vIn this device the veneer sheets are joined together by the hammering effect produced by the vibrator.

l partment 45' in the lblock 38, pressurebeing applied through a hose 45. The plastic composition is maintained in a melted condition by the heating element 48 in the block 33. The sides of the block, being in contact with the sheets 4| and 42, preheat them for the plastic the points behind the points of application of composition. Suitable controlling devices may be, ot course. provided for maintaining desired temperature oi the plastic composition; also for applying desired pressure to the roller.

It should be understood that the term thermoplastic used herein includes all such plastic compositions which require heat ior their moulding. regardless of whether they retain their property to be softened by the subsequent application ot heat, or become permanently solidified upon cooling.

It is understood that my device for forming laminated sheet bodies may be further modified without departing from the spirit of the invention. as setlforth in the appended claims.

I claim as my invention:

1. A method oi' forming a composite laminated sheet, consisting in joining together at least two strips of sheet material with a layer of a substance therebetween having thermoplastic properties, imparting to the sheet the desired curvature. applying heat without pressure to successive points of the sheet in a continuous movement, and applying pressure with heat extraction to heat.

2. A method o1' forming a composite laminated sheet. consisting in Joining together at least two strips of sheet material with a layer of a substance therebetween having thermoplastic properties, imparting to the sheet the desired curvature, applying radiant heat withoutpressure to successive points of the sheet in a continuous movement, and applying pressurewith heat extraction to the points behind the points of ap plication of heat.

FRANCIS M. WEIR. 

